question_answer

A particle is kept at rest at the top of a sphere of diameter 42 m.  When disturbed slightly, it slides down.  At what height ?h? from the bottom, the particle will leave the sphere                                     [BHU 2003]

A)             14 m

B)                      28 m

C)             35 m   

D)             7 m

Correct Answer: C

Solution :

                As we know for hemisphere the particle will leave the sphere at height \[h=2r/3\]             \[h=\frac{2}{3}\times 21=14\,m\]                    but from the bottom             \[H=h+r=14+21=35\,metre\]